An electric car driven by an electric motor and a hybrid car driven by both an electric motor and an engine require an electric power supplying high-voltage electric power to the electric motor for smooth driving. An electric power supply structured by connecting a plurality of relatively small batteries in series (see Patent Document 1) is mounted in the electric car and the hybrid car.
FIG. 13 is a plan view of an electric power supply by prior art. The electric power supply includes a battery assembly (not shown) and a busbar module 105 overlapped on the battery assembly. The battery assembly includes a plurality of batteries. The plurality of batteries is held to be arranged along one direction so as to array a positive electrode of one battery and a negative electrode of another battery adjacent to the one battery corresponding to each other.
The busbar module 105 includes a plate 150 and a plurality of busbars 101. The plate 150 is formed by insulation synthetic resin to have a top shape same as that of the battery assembly as a whole. The top plate 150 includes a plurality of busbar receiving sections 152 receiving the busbar 101. Each of the busbar receiving sections 152 includes a bottom wall 152a, on which the busbar 101 is overlapped, having a hole communicating with a later-described hole 123 of the busbar 101 and a plurality of side walls 152b extending vertically from outer edges of the bottom wall 152a, and the busbar receiving section 152 is formed into a box shape having an opening at a top thereof.
The busbar 101 is formed into a rectangular shape by pressing an electric conductive metal sheet. The busbar 101 includes a pair of holes 123 passing a positive electrode and a negative electrode adjacent to each other of adjacent batteries.
When the electric power supply mentioned above is assembled, the busbar 101 is mounted at the busbar receiving section 152 of the plate 150 so as to communicate the hole 123 of the busbar 101 and the hole of the busbar receiving section 152. The electrode of the battery is inserted through the holes communicated with each other, and the busbar module 105 is overlapped on the battery assembly, and a nut is screwed to the electrode. Thereby, each busbar connects the electrodes adjacent to each other of the batteries adjacent to each other, so that the plurality of busbars 101, that is the busbar module 105, connects the plurality of batteries in series. Thus, the electric power supply is assembled.
For exerting maximum performance of the electric power supply, it is required to monitor remaining capacity (voltage value) of each battery. For this purpose, the batteries of the electric power supply mentioned above maybe connected through electric wires 106 as a circuit body with an ECU (electronic control unit) as a control device.
The electric wire 106 is a covered electric wire having an electric conductive core wire 161 and an insulation cover 162 covering the core wire 161. The cover 162 at one end of the electric wire 106 is peeled and removed so as to expose the core wire 161. The one end of the electric wire 106 is connected with a voltage detecting terminal 109.
The voltage detecting terminal 109 is formed by pressing a conductive metal sheet, and includes integratedly a battery connecting portion 191 connected with the electrode of the battery (busbar 101) and a wire connecting portion 192 connected with the electric wire 106. The battery connecting portion 191 is formed into a square shape having about a half size of the busbar 101, and includes a hole 193 passing the negative electrode or the positive electrode of the battery at a central area of the battery connecting portion 191. The wire connecting portion 192 includes a bottom plate portion having a rectangular plate shape and continuing an outer edge of the battery connecting portion 191, and a plurality of clamp pieces continued to both side ends along a widthwise direction of the bottom plate portion.
The exposed core wire 161 of the one end of the electric wire 106 is overlapped on the bottom plate portion of the wire connecting portion 192, and connected with the voltage detecting terminal 109 by clamping the clamp pieces. The electrode of the battery is passed through the hole 193 and the battery connecting portion 191 is overlapped on the busbar 101 in the busbar receiving section 152, and the nut is screwed to the electrode, and thus, the voltage detecting terminal 109 is connected with the electrode of the battery (busbar 101). The other end of the electric wire 106 is connected with a connector so as to be connected to the ECU through the connector. Thus, the battery of the electric power supply and the ECU are connected through the electric wire 106 and the voltage detecting terminal 109 (and the busbar 101), and the remaining capacity of each battery is monitored.